Not sit-ups, planks, or crunches: I do this simple Pilates exercise every single day to build a strong and stable core and work on my hip flexor mobility

While exercises like sit-ups and crunches work the rectus abdominis, or "six-pack" muscles, this simple-looking exercise ...

4 Standing Exercises That Flatten Side Belly After 45, According to a Trainer

Side belly exercises after 45: 4 standing moves that hit the obliques and tighten your waist, from Jarrod Nobbe, MA, CSCS.